Sodium carbonate (also known as washing soda, soda ash, and soda crystals) is a white, odorless, inorganic compound. Its salts are soluble in water, giving an alkaline solution. It is usually produced by the Solvay process by reacting sodium chloride with calcium carbonate (limestone) in the presence of ammonia as a catalyst. In some areas of the world, sodium carbonate is extracted from trona ore. Sodium carbonate is used as an input in many industries, especially the glass, ceramics, industrial detergents, and paper industries. It is also used to manufacture sodium compounds such as borax. Some grades of it are also used in the food industry, such as baked goods, and are called baking soda.